Heat-adhesive paper sheet

ABSTRACT

A heat-adhesive paper sheet suitable for use as fusuma paper and shoji paper in a Japanese style house, wallpaper, ceiling paper, liner for paintings and calligraphic works, and liner for plywood, and which is adhered to the object with heat by ironing. The heat-adhesive paper sheet is composed of a paper sheet material having a projection-depression pattern formed on the surface thereof by creping or embossing or the like and a layer of a thermoplastic thermal shrinking pressure-sensitive adhesive provided on one surface of the paper sheet material. Even though the surface of the object to which the paper sheet is stuck is somewhat rough and uneven, the heat-sensitive adhesive layer may easily be fused so that the paper sheet may be well applied to the object under light pressure without forming wrinkles on the applied sheet. Steam ironing, which has heretofore been unacceptable, is applicable to this paper sheet for sticking it to an object.

FIELD OF ART

The present invention relates to a heat-adhesive paper sheet, which issuitable for use as wallpaper, ceiling paper, or as a liner for plywood,especially as a sliding door, fusuma paper or a paper-sliding screen,shoji paper in a Japanese style house, or as a linear for paintings andcalligraphic works, and which can be applied with not only an ordinaryiron but also a steam iron.

BACKGROUND OF THE INVENTION

Hitherto, as paper material sheets such as wallpaper, ceiling paper orliner for plywood, especially fusuma paper or shoji paper in a Japanesestyle house or liner for paintings and calligraphic works, there areknown a rewettable fusuma paper or wallpaper having a water-solublepaste as coated and dried thereon, a so-called tacking type adhesivesheet composed of a paper sheet base coated with a release paper via anadhesive therebetween, and a so-called ironing type adhesive sheet.

The above-mentioned water-soluble paste-coated rewettable fusuma paperor wallpaper is prepared by previously coating a water-soluble paste,which is naturally coated to the back surface of said fusuma paper orwallpaper with a brush or roll just before applying the paper to afusuma or wall, followed by drying the coated paste thereon in the stepof forming the fusuma paper or wallpaper. In assuring a smooth and evenadherence of the water-soluble paste-coated rewettable fusuma paper orwallpaper to a fusuma or wall, the amount of water to be applied to thepaper for rewetting has a great influence on the finished condition. Ifthe amount of water applied thereto is too small, the paper will adhereto the surface of a fusuma or wall before the wrinkles in the paperformed during sticking operation have been stretched out, so that theadhered paper is affixed with wrinkles. On the other hand, if the amountof water applied is too large, the wrinkles formed during the stickingoperation could well be stretched but, when the paper base is made ofpulp or a similar water-absorbing sheet, the sheet will shrink and drawback the four edges of the sheet before adhesion. As a result, the areaof the paper in the finished state is reduced. Fusuma paper that isapplied to fusuma in such a way will leave a paperless space between thefusuma paper and the fusuma frame, which is unfavorable. Similarly, theshrunken wallpaper as applied to a wall causes paperless gaps in thepaper-to-paper joint area, which are also unfavorable. The amount ofwater to be applied to a rewettable fusuma paper or wallpaper of thekind varies, depending upon the ambient humidity, so that adjustment ofthe amount of water to be applied thereto requires high-level of skill.

A so-called tacking type fusuma paper or wallpaper is a means ofavoiding the difficult watering process involved in the above-mentionedrewettable fusuma paper or wallpaper. Application of such tacking typefusuma paper or wallpaper to a fusuma or wall is effected by peeling therelease paper previously applied to the back surface of the paper sothat, with the finish of the sticking operation, the papering of thefusuma or wall is finished. This tacking type fusuma paper or wallpaperhas various advantages in that the sticking operation is effectedrapidly and that the operating environment is not messy as no water isneeded for sticking. However, it has drawbacks in that, sincere-sticking is impossible, the stuck paper is often wrinkled and thepaper itself is high-priced.

An ordinary ironing type fusuma paper includes a modified type of theabove-mentioned rewettable fusuma paper where only the four edges of thepaper are dried with a household iron during sticking, and a fusumapaper sheet having a heat-sensitive adhesive laminated or coated on theback surface thereof. The advantages of the former are that the stuckpaper hardly wrinkles even if an excess amount of water has been appliedto the rewettable fusuma paper, as the peripheral edges of the wettedpaper are dried and stuck with an iron. Also the area of the appliedpaper is not reduced. However, as it needs watering, it has variousdrawbacks in that the number of operating steps is complicatedly morethan with the ordinary rewettable paper and that the operatingenvironment becomes dirty.

The latter heat-sensitive adhesive laminated or coated sheet is one asprepared by laminating or coating a heat-sensitive adhesive onto theback surface of a fusuma paper sheet which is used in an ordinaryrewettable fusuma paper, by roll coating or lamination. It is said tohave various advantages in that it may easily be stuck without deframingthe fusuma, without water and by anyone with a few tools. Sticking mayalso be effected rapidly because of the characteristic dry adhesion. Infact, however, it has various drawbacks in that it must be stuck only toan evenly planed surface, that it cannot be stuck to a fusuma having anuneven or rough surface, that when it is stuck to a fretwork fusuma, theshade of the inner frets would appear if sticking is effected under toomuch pressure, and that since no water can be used in sticking, thepaper would be elongated to cause wrinkles or swollen areas even thougha water mist is applied thereto in sticking. Because of these reasons,only a dry iron can be used. No steam iron can be used, even though itis known that a steam iron is effective for stretching wrinkles out ofthe paper sheet and for rapid sticking of the paper.

In particular, in the conventional heat-adhesive paper sheet, since thepaper material itself is naturally applicable by sticking with awater-soluble paste, application of water thereto causes increase of thewater content to result in elongation of the paper sheet, while decreaseof the water content by drying results in reduction of the same.Therefore, in sticking with an ordinary iron, there occurs still anotherdrawback in that the water content in the paper material decreasesduring sticking under heat to yield wrinkles, while the water contenttherein increases after completion of sticking and the size of the stuckpaper is enlarged to cause swelling in the area of the paper withsticking failure.

Therefore, the surface to which a conventional heat-adhesive paper sheetis stuck must be thoroughly planed and flat so that uniform pressure maybe applied by ironing, and a high-temperature ironing is needed for thesticking.

The object of the present invention is to provide a heat-adhesive papersheet, which may be well applied even to an object having an unevensurface, which may be stuck with a steam iron, which may have a goodsurface condition after sticking, and which may accurately be stuck evenat a relatively low temperature in a short period of time.

DISCLOSURE OF THE INVENTION

The heat-adhesive paper sheet of the present invention is characterizedby having a thermoplastic thermal shrinking pressure-sensitive adhesivelayer on the surface of a sheet material having a projected-depressionpattern thereon as formed by creping or embossing.

Regarding creping for forming the projection-depression pattern, thereare mentioned two creping means of wet-creping and dry-creping. Both maybe employed in the present invention.

The unit size (h) of the projection-depression pattern (height of oneprojection on one surface) to be effected by creping or embossingvaries, depending upon the thickness (D) of the sheet, and is mostdesirable at approximately 1/2 to 50 times the thickness (D) of thesheet for creping. This is because, if the projection size (h) bycreping is less than 1/2 of the thickness (D) of the sheet, theinfluence of elongation and shrinkage of the sheet is directlytransferred to elongation and shrinkage of the area thereof; while if itis more than 50 times of the same, the projection-depression patternwould mar the appearance of the paper sheet and would cause unevenadhesion and uneven outward appearance of the sheet. On the other hand,where the projection-depression pattern on the sheet is made byembossing, the optimal depth of the embossing pattern on the embossingroll to be used is from approximately 1/2 to 50 times the thickness (D)of the sheet. In embossing, the sheet is compressed during the embossingprocess so that the thickness of the sheet decreases and the embossedprojection-depression pattern of the processed sheet would be partlyelastically restored, whereby the size (h) of the projection-depressionpattern on the embossed sheet would somewhat be smaller than the depthof the embossing pattern on the embossing roll used. However, it hasbeen ascertained by experiments that where the depth of the embossingpattern of the embossing roll to be used is within the above-definedrange, the projection-depression pattern as formed on the sheet byembossing may be selectively elongated or shrunk together with theelongation or shrinkage of the sheet so that the sheet is not wrinkled.In addition, even though the surface of an object to which the adhesivesheet of this invention is stuck is somewhat uneven, the suitabledepressions on the back surface of the sheet could adhere well to theuneven surface of the object so that the sheet may generally adhere wellto the surface of the object. Where the size (h) of the depression onone surface of the sheet is from approximately 1/2 to 50 times thethickness (D) of the sheet, the size (H) of the projection-depressionpattern of both surfaces of the sheet is to be from approximately 3/2 to50 times the thickness (D) of the sheet.

As mentioned above, since the surface of the sheet is to have aprojection-depression pattern formed by creping or embossing, when thehot-pressed area of the adhesive sheet of the invention shrinks insticking, the height of the projection-depression pattern that is in theboundary area between the hot-pressed area and the non-hot-pressed areais decreased so that the shrinkage of the hot-pressed area does notinfluence the non-hot-pressed area, and so, no wrinkles are formed inthe boundary area or the adjacent area. After the sheet has beenapplied, elongation or shrinkage of the sheet caused by fluctuation ofthe humidity or the ambient temperature does not extend in the planedirection but may be absorbed by the cross-sectional elongation andshrinkage of the projections and depressions on the both surfaces of thesheet. As a result, the sheet has no wrinkles.

As the sheet material mentioned above, a synthetic resin sheet having aliner made of a wood pulp mixture may be used in addition to a so-calledordinary paper.

As paper for the sheet material, one made from only thermal shrinkingfibers themselves may be used, as well as one made from a mixturecontaining thermal shrinking fibers.

For instance, one may use paper made from a single substance of naturalbast fibers of, for example, paper mulbery, mitsumata (Edgeworthiapapyrifera), gampi (Wikstroemia sikokiana) or hemp, or cellulose, fibersof, for example, wood pulp, cotton linter pulp or rayon, or from acomposite substance of them.

To the above-mentioned raw material, may be added inorganic fibers suchas glass fibers, micro glass, rock wool, slag wool, alumina fibers,alumina-silica fibers, mullite fibers, boric acid fibers, quartz fibers,silicate glass fibers, molten silica fibers, potassium titanate fibers,zirconia fibers, calcium sulfate fibers, phosphate fibers, borosilicatefibers, carbon fibers, active carbon fibers, etc.

Further, vinylon fibers may be added thereto.

As the case may be, and in accordance with the use, silicates such aspagodite, kaolin, sericite, talc or zeolite, as well as other fillerssuch as calcium carbonate, titanium dioxide, aluminum hydroxide,alumina, silica or magnesia can be added to the material.

Further, various organic binders, including a paper strength enhancersuch as water-soluble urea resin, melamin resin, cationated starch, CMCpolyamido-polyamine-epichlorohydrin resin, polyimine resin,water-soluble acrylic resin, methyl cellulose, ethyl cellulose orhydroxyethyl cellulose, as well as sizing agents such as maleic acidneutral sizing agent, rosin sizing agent, petroleum sizing agent, highpolymer resin emulsion or rubber latex may also be added thereto.

In addition, polyvinyl alcohol or SPG may also be employable as abinder.

As another employable embodiment, the above-mentioned paper is used as aliner, the surface of the liner is coated with a vinyl chloride resin,the coated resin is treated to make it air-permeable by the techniqueillustrated in Japanese Patent Unexamined Publication No. 59-88998, andthe surface of the paper sheet is subjected to various decorative andother necessary for wallpaper, including printing, foaming, embossing,flame-proofing or fire-retardation treatment.

As still another employable embodiment, the above-mentioned paper isused as a liner, and the surface of the liner is laminated with a wovenfabric, knitted fabric, non-woven fabric, heat-resistant syntheticleather, thin cork skin, thin wood skin (for relief laminate), metalfoil, mineral net or natural leather, or a composite of such, in a waythat the resulting laminate is steam-permeable.

In addition to the above-mentioned substances, any and every other knownbase sheet for wallpaper, which may allow permeation of ironing steamand which neither shrinks too much nor fuses with ironing heat, may beused in the present invention.

As the above-mentioned paper, paper containing hydrophobic thermalshrinking fibers may be used. For the purpose of improving thedimensional stability of the base sheet when exposed to fluctuation ofambient humidity and temperature, the paper for use in the inventionpreferably contains from 5 to 100% of hydrophobic thermal shrinkingfibers.

More specifically, it is desirable for the paper to be composed of from5 to 100% hydrophobic thermal shrinking fibers so that the heat-adhesivepaper sheet may shrink during the application of the sheet and that,after completion of application, the adhered sheet may have improveddimensional stability when exposed to fluctuation of ambient humidityand temperature.

From among the above-mentioned paper materials, formulations suitable tothe use of shoji paper or liner for paintings and calligraphic works areselected. For laminate paper, those not causing peeling of therespective laminate layers are selected.

The surface of the paper sheet for use in the present invention may beprinted by flexo-printing, gravure-printing or screen-printing or may beresin-coated for the purpose of protecting it from staining, or it mayfurther be processed for other decoration. In any case, the thusprocessed paper sheet must be steam-permeable for applicability to steamironing.

Where the above-mentioned paper material is used as a liner and thesurface thereof is coated with a vinyl chloride resin, it is firstprocessed for imparting gas-permeability thereto by the method describedin Japanese Patent Unexamined Publication No. 59-88998 so that it may besteam-permeable. Thereafter, any other necessary processing, such asprinting, foaming, embossing, flame-proofing, or fire-retardationtreatment, is applied thereto.

In addition, the liner may be a steam-permeable sheet laminated with awoven fabric, knitted fabric, non-woven fabric, heat-resistant syntheticresin layer, thin cork skin, metal foil, mineral net or leather on thesurface thereof.

For forming other sheets of the invention applicable to steam-ironing,any materials may be employed which neither shrink too much nor becomefused by the heat in ironing.

As hydrophobic thermal shrinking fibers for use in the invention,suitable are fibers of a single substance of polyethylene,polypropylene, polyester, polychlal, acrylic polymer, polymers of vinylacetate or derivatives thereof, or of a composite substance of them.Suitable fibers and their content may be determined in accordance withthe property of the article to which the adhesive sheet is applied.

The heat-sensitive adhesive to be used in preparing the sheet of theinvention may be selected from EVA, EEA, EAA, ionomer resins, urethaneresins and derivatives of them having a melting point from 60° C. to150° C., in accordance with the use of the sheet, and the thickness ofthe adhesive layer in the sheet may be selected from the range of 10 to100 μm, preferably from 15 to 50 μm, for the purpose of attainingsuitable adhesion power and shrinking power.

As an adhesive layer, it is preferable to laminate a thermoplastic,thermal shrinking, pressure-sensitive adhesive synthetic resin film onthe paper sheet material to form a laminated adhesive layer thereonhaving a thickness from approximately 10 to 100 μm, preferably from 15to 50 μm. Since the adhesion power and shrinking power are required, ifthe thickness of the layer is less than 10 μm, the filmed layer will beuneven so that the adhesion power and shrinking power would be too weak.On the other hand, if it is more than 100 μm, sufficient heating of thepaper sheet with a household iron will be impossible in a short periodof time so that adhesion and shrinkage would be unfavorably uneven.

As the above-mentioned synthetic resin for forming the adhesive layer,there are concretely mentioned ethylene-vinyl acetate copolymer (EVA),ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer(EAA), ionomer resins, urethane resins and derivatives of them, whichhave a melting points from 60° to 150° C. From among them, thosesuitable may be selected for use in the present invention.

In accordance with the present invention, since the sheet has aprojection-depression pattern as formed by creping or embossing, theheight (or depth) of each projection and each depression in the boundaryarea between the hot-pressed area and the non-hot-pressed area decreaseswhen the hot-pressed area is shrunk for adhesion, so that the influenceof the shrinkage of the hot-pressed area is not transmitted to thenon-hot-pressed area, and therefore the boundary area and the adjacentarea do not shrink. After adhesion, elongation or shrinkage of the sheetdue to fluctuation of ambient humidity or temperature does not extend tothe plane direction of the sheet but is absorbed by elongation orshrinkage of the projections and depressions (as being on the surface ofthe sheet) in the cross-sectional area. As in result, the sheet does notshrink despite the fluctuation of ambient humidity or temperature afteradhesion.

The heat-adhesive paper sheet of the present invention may be applied toan object as in the following example.

First, a heat-adhesive paper sheet of the present invention, having asomewhat larger area than the area to which it will be applied, isapplied to the intended surface, and the four corners of the sheet arelightly hot-pressed with a household steam iron heated at 180° to 200°C., the pressing power being about equal to the weight of the iron used.The reason why a steam iron is used for the hot-pressing is as follows:The surface of the object to be covered with the paper sheet isgenerally uneven. For instance, where a heat-adhesive paper sheet of theinvention is applied to a fretwork fusuma by hot-pressing, thepressure-sensitivity noticeably differs between the frets and thefret-free plane base in the fretwork fusuma. Regarding a sliding fusuma,the bottom surface of an iron could not be uniformly applied to thewarped and uneven surface of the fusuma. As a result, where the pressingpower is not sufficient, the amount of heat to be transmitted to theadhesive paper sheet is insufficient when an ordinary dry iron is used,so that the layer of the heat-sensitive adhesive in the sheet will notheat to the melting point and will often cause adhesion failure.However, if a steam iron is used in place of a dry iron, not only theheat conduction of the sheet itself but also the heat conduction of thesteam from the iron may be evenly attained so that sure adhesion of thesheet is achieved without elevating the temperature of the iron used tosuch a high temperature that the sheet burns.

Next, the excess area of the (temporarily) adhered paper sheet are cutoff and hot-pressure adhesion of the four corners of the sheet iseffected to determine the position thereof on the object. For finallysticking the center part of the sheet, the sheet is gently ironed fromthe center part to the periphery area in order, the ironing pressurebeing equal to the weight of the iron and the light hand-pressure of theoperator. Lastly, the four edges of the sheet are slowly hot-pressed.Accordingly, the adhered condition of the four edges of the sheet issuch that the projections of the sheet are made flat because of the hotpressure applied thereto so that the contact area is enlarged andsufficient adhesion of the sheet to the object is attained.

Since the center part of the sheet is heated and lightly pressed, thesheet is shrunk and the whole is thereby stretched. However, since thesheet has a projection-depression pattern as formed by creping orembossing, superfluous shrinkage of the sheet in the plane direction maybe absorbed by the shrinkage of the projections and depressions in theheight (or depth) direction so that the sheet is neither shrunk in theplane direction nor wrinkled. The back of each depression of theprojection-depression pattern of the sheet is adhered to the object.More precisely, the four edges of the sheet are adhered to the object byplane contact, while the center part is adhered thereto microscopicallyby spot contact or line contact. Therefore, even though the appliedsheet is elongated or shrunk because of variations in ambient humidityand temperature, the non-adhering portions except for theabove-mentioned spot-stuck or line-stuck portions are elongated orshrunk in the thickness direction so that the sheet is neither badlywrinkled nor badly swollen.

The heat-adhesive paper sheet of the present invention, having theabove-mentioned constitution, displays the following advantageouseffects.

1 Where a part of a broad sheet is hot-pressed with an iron to adhere itto an object, the shrinkage of the hot-pressed area in the planedirection may be well absorbed by shrinkage of the projections anddepressions in the height (or depth) direction, so that the sheet is notwrinkled.

2 After adhesion of the sheet, the elongation and shrinkage of the sheetdue to fluctuation of ambient humidity and temperature may be absorbedby elongation or shrinkage of the projections and depressions in theheight (or depth) direction, so that the sheet is neither wrinkled norswollen.

3 The sheet may be used as fusuma paper, shoji paper, wallpaper, linerfor paintings and calligraphic works, or liner for plywood, and may beeasily adhered to the object, without forming wrinkles in the adheredsheet, by anyone with household appliances.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an enlarged cross-sectional view of a heat-adhesive papersheet of an embodiment of the present invention.

In the drawing, 1 is a heat-adhesive paper sheet of the embodiment; 2 isa paper or synthetic resin sheet (hereinafter referred to as a "sheet")which is a sheet base; and 3 is a layer of a thermoplastic, thermalshrinking, pressure-sensitive adhesive (hereinafter referred to as an"adhesive layer").

The heat-adhesive paper sheet 1 is one as prepared by formingprojections and depressions on the surface of the sheet 2 by creping orembossing, followed by forming the adhesive layer 3 on one surface ofthe sheet 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT EXAMPLE 1

For the sheet 2 of the drawing, a fusuma paper having a weight of 100g/m² and a thickness of 150 μm was used. For the adhesive layer 3 of thesame, a 30 μm film of EVA resin was laminated. The sheet was embossedwith an embossing roll, the embossing pattern having a depth of (a) 0μm, (b) 50 μm or (c) 250 μm. Referring to the iron shrinkage test methodfor woven fabric and knitted fabric of JIS-L-1057, the adhesive sheetsample was tested, whereupon the elongated or shrunk condition, if any,of the sample was examined. Wrinkles, if formed, were checked with thenaked eye. The results obtained are shown in Table 1 below.

                  TABLE 1                                                         ______________________________________                                                      Direct                                                                        Elongation                                                                              Wrinkles                                                            or        in        Evaluation                                         Iron   Shrinkage Boundary  (*)                                         ______________________________________                                        B-1      Dry      -0.5%     Yes     X                                         (comparative                                                                  example)                                                                      B-2      Steam    -0.3%     Yes     X                                         (comparative                                                                  example)                                                                      a-1      Dry      -0.3%     Yes     X                                         (comparative                                                                  example)                                                                      a-2      Steam    -0.4%     Yes     X                                         (comparative                                                                  example)                                                                      b-1      Dry      -0.25%    Yes     X                                         (comparative                                                                  example)                                                                      b-2      Steam    -0.3%     Yes     X                                         (comparative                                                                  example)                                                                      c-1 (example                                                                           Dry      -0.2%     No      ◯                             of the                                                                        invention)                                                                    c-2 (example                                                                           Steam    -0.6%     No      ⊚                          of the                                                                        invention)                                                                    ______________________________________                                         (*) The ironed result was evaluated on the basis of wrinkles, if formed,      in the boundary between the hotpressed area and the nonhot-pressed area.      indicates a poor evaluation; ◯ indicates good; and                ⊚ indicates the best.                                     

Ironing Condition:

Temperature: 200° C.

Pressure: 7.5 gf/cm²

Speed: 10 cm/sec, for 3 forward-backward movements

Amount of Steam Generated: 8 g/min

The ironing bed used was composed of 10 mm-thick plywood and 0.25 mmpaper as attached thereto, covered with 15 g/cm² rayon paper sheet sothat the heat-sensitive adhesive would not adhere to the bed.

Results:

B-1 (No adhesive layer):

This displayed thermal (dry-heat) shrinkage of the paper itself.

B-2 (No adhesive layer):

This displayed wet-heat shrinkage of the paper. The reason why it hadless shrinkage than B-1 is because it had a high water content.

a-1:

This displayed less shrinkage than B-1 because the amount of heattransmitted to the heat-sensitive resin was insufficient.

a-2:

This displayed more shrinkage than a-1 because heat conduction by steamwas sufficient to cause the heat-sensitive resin to shrink.

b-1 and b-2:

This was almost same as a-1 and a-2, but the amount of transmitted heatwas less because of the increased apparent thickness of the paper causedby the embossed projection-depression pattern. As a result, theshrinkage was less than with a-1 and a-2.

c-1:

Thermal conduction to the heat-sensitive resin was insufficient becauseof the enlarged projection-depression pattern formed by embossing sothat the shrinkage was slight. However, with slow heating, a sufficientpercentage of shrinkage could be obtained.

c-2:

As compared with c-1, the percentage of shrinkage was higher. This isbecause thermal conduction was improved due to application of steam, soshrinkage of the heat-sensitive resin was attained. Despite the largepercentage of shrinkage, no wrinkles formed in the boundary between thehot-pressed area and the non-hot-pressed area. This is because theembossed projection-depression pattern absorbed the area shrinkage.

Example 2

Linear samples for paintings and calligraphic works, which are stuck byironing, were prepared by forming a 20 μm-thick EVA resin on a paperbase having a weight of 50 g/m² and a thickness of 110 μm, followed bycreping them to make the height of the creped projection 0 μm (sampled), 40 μm (sample e) or 150 μm (sample f), respectively. This wassubjected to an elongation-shrinkage test with reference to JIS-L-1057,to examine the condition of the tested samples. The results obtained areshown in Table 2 below.

                  TABLE 2                                                         ______________________________________                                                      Direct                                                                        Elongation                                                                              Wrinkles                                                            or        in        Evaluation                                         Iron   Shrinkage Boundary  (*)                                         ______________________________________                                        C-1      Dry      -0.5%     Yes     X                                         (comparative                                                                  example)                                                                      C-2      Steam    -0.3%     Yes     X                                         (comparative                                                                  example)                                                                      d-1      Dry      -0.8%     Yes     X                                         (comparative                                                                  example)                                                                      d-2      Steam    -0.7%     Yes     X                                         (comparative                                                                  example)                                                                      e-1      Dry      -0.8%     Yes     X                                         (comparative                                                                  example)                                                                      e-2      Steam    -0.7%     Yes     X                                         (comparative                                                                  example)                                                                      f-1 (example                                                                           Dry      -0.6%     No      ◯                             of the                                                                        invention)                                                                    f-2 (example                                                                           Steam    -0.5%     No      ⊚                          of the                                                                        invention)                                                                    ______________________________________                                         (*) The ironed result was evaluated on the basis of wrinkles, if formed,      in the boundary between the hotpressed area and the nonhot-pressed area.      indicates a poor evaluation; ◯ indicates good; and                ⊚ indicates the best.                                     

Ironing Condition:

Temperature: 180° C.

Pressure: 7.5 gf/cm²

Speed: 10 cm/sec, for one forward-backward movement

Amount of Steam Generated: 4 g/min.

The ironing bed used was composed of 10 mm-thick plywood and 0.25 mmpaper as attached thereto, covered with 15 g/cm² rayon paper sheet sothat the heat-sensitive adhesive would not adhere to the bed.

Results:

As compared with the samples of Example 1, thermal conduction of thesamples of the present example was better and the percentage ofshrinkage was greater since the thickness of the linear was 1/2 of thatof the fusuma paper of Example 1. Therefore, the heat-sensitive resin inthe present example shrank more than that in Example 1, but almost thesame results as those in Example 1 were obtained by the present examplewith respect to the presence or absence of the creped pattern or thesize of the creped projections and depressions. In samples f-1 and f-2,no wrinkles formed in the boundary between the hot-pressed area and thenon-hot-pressed area despite the large percentage of shrinkage. This isbecause the creped projections and depressions absorbed the areashrinkage, as in the case of Example 1.

Example 3

This example shows a comparison of the adhesion strength of twoheat-adhesive paper sheet samples each having a different embossedprojection-depression pattern with different ironing. The results areshown in Table 3 below.

                  TABLE 3                                                         ______________________________________                                                 Small Projection-                                                                           Large Projection-                                      Ironing  Depression Pattern                                                                          Depression Pattern                                     ______________________________________                                        Dry       40 g         10 g                                                   Steam    128 g         32 g                                                   ______________________________________                                    

Evaluation Method:

In accordance with the laminate sheet layer peeling strength test methodof JIS-P-8139, the peeling strength was measured to be the adhesionstrength.

Ironing Condition:

Temperature: 200° C.

Pressure: 7.5 gf/cm²

Speed: 10 cm/sec, one time

Amount of Steam Generated: 8 g/min.

Results:

1 Regarding the size of the embossed projection-depression pattern, theadhesion strength of the sample having a smaller projection-depressionpattern is larger. From the result, it is understood that the adhesionstrength is influenced by the contact area.

2 Regarding the ironing by the dry-ironing or steam-ironing, it isunderstood that the steam-ironed sample had roughly three times thepeeling strength of the dry-ironed sample, irrespective of the size ofthe embossed projection-depression pattern. The result indicates thatthe amount of the transmitted heat in steam ironing is three timeslarger than that in dry ironing, from which it is understood that thesteam ironing less likely causes uneven adhesion than the dry ironingless likely causes uneven adhesion than the dry ironing.

Example 4

The percentage of heat shrinkage and elongation in water of variousheat-adhesive paper sheet samples was measured, and the results obtainedare shown in Table 4 below.

                  TABLE 4                                                         ______________________________________                                        Kind of  Heated, 5   In Water, 5 Maximum                                      Paper    minutes     minutes     Elongation                                   ______________________________________                                        g        -0.4%        1%       1.4%                                           h        -0.4%        2.5%     2.9%                                           i-1      -0.6%       -0.15%    0.45%                                          i-2      -0.75%      -0.30%    0.45%                                          i-3      -0.90%      -0.90%    0%                                             ______________________________________                                    

Measurement Condition:

Using a JIS in-water elongation measuring machine, heat shrinkage andin-water elongation of the test pieces above were continuously measured.In measurement of heat shrinkage, hot air having a constant temperatureof 120° C. was applied to the test pieces for 2 minutes.

Subsequently, the in-water elongation was measured by dipping the testpieces in water for 5 minutes. After thus dipped, the elongated size ofeach piece was measured.

The test samples were as follows:

g: wallpaper base (pulp 100%)

h: fusuma paper base (containing rayon)

i-1: 20% hydrophobic thermal shrinkage fiber-containing paper

i-2: 30% hydrophobic thermal shrinkage fiber-containing paper

i-3: 100% hydrophobic thermal shrinking fiber paper

Results:

1 Regarding percentage of the heat shrinkage, i-1, i-2 and i-3 sampleshad a larger value than g and h samples. This is considered in theformer i-1, i-2 and i-3 samples would have shrunk.

2 Regarding the in-water elongation, g and h samples showed 1 to 2.5%elongation, while i-1, i-2 and i-3 samples were shorter than theoriginal length. However, with respect to the maximum elongationpercentage, which indicates elongation of a previously heat-shrunksample after being dipped in water for 5 minutes, all the g, h, i-1 andi-2 samples were elongated. However, the maximum elongation percentageof i-1 and i-2 samples was 1/3 to 1/6 of that of g and h samples. Theformer two showed a slightly minus elongation from the original testbefore heated. The i-3 sample showed no elongation from shrunken size byheat.

Where a heat-adhesive paper sheet is stuck to an object with a householdiron, it is desirable if the sheet shrinks in some degree during ironingand does not elongated after the ironing operation. From this viewpoint,i-1, i-2 and i-3 samples are better than g and h samples.

INDUSTRIAL FEASIBILITY

The heat-adhesive sheet of the present invention may well be adhered toan object having a somewhat rough and uneven surface, since theheat-sensitive adhesive layer of the sheet may easily be fused. Inaddition, using a steam iron, it may be well applied to the surface ofan object at a relatively low temperature under light pressure withoutforming wrinkles in the stuck sheet. Therefore, it may be preferable foruse as fusuma paper in a Japanese style house, a backing layer forOriginal paintings and calligraphic works, an overcoating sheet forwalls, ceilings and doors of ordinary houses, and as a liner forplywood.

I claim:
 1. A heat-adhesive paper sheet which adheres by the pressure ofa steam iron without causing creases on an outer surface of said sheet,said sheet comprising:a steam-permeable paper sheet material having auniform projection-depression pattern formed by creping, said patternhaving a height ranging from 1/2 to 50 times the thickness of the sheet,and a layer of thermoplastic, thermal shrinking, pressure-sensitiveadhesive having a melting point in the range Of 60° C. to 150° C.provided on one surface of the paper sheet material, said layer having athickness in the range of approximately 10 to 100 μm.
 2. A heat-adhesivepaper sheet which adheres by pressure with a steam iron without causingcreases on an outer surface of said sheet, said sheet comprising:asteam-permeable paper sheet material having a uniformprojection-depression pattern formed by embossing, said pattern having aheight ranging from 1/2 to 50 times the thickness of the sheet, and alayer of thermoplastic, thermal shrinking, pressure-sensitive adhesivehaving a melting point of 60° C. to 150° C. provided on one surface ofthe paper sheet material, said layer having a thickness in the range ofapproximately 10 to 100 μm.
 3. A heat-adhesive paper sheet which adheresby pressure with a steam iron without causing creases on an outersurface of said sheet, said sheet comprising:a steam-permeable papersheet material having one surface thereof embossed with an embossingroll having an embossing pattern thereon so as to provide a uniformprojection-depression pattern on said one surface, with a depth rangingfrom 1/2 to 50 times the thickness of said sheet, and a thermoplastic,thermal shrinking, pressure-sensitive adhesive layer having a meltingpoint of 60° C. to 150° C., coated on one side of said paper sheetmaterial, said adhesive layer having a thickness in the range ofapproximately 10 to 100 μm.
 4. A heat-adhesive paper sheet as in claimedin any one of claims 1 to 3, in which said steam-permeable paper sheetmaterial is a paper material containing hydrophobic thermal shrinkingfibers ranging from 5 to 100% of said paper sheet material.
 5. Aheat-adhesive paper sheet as claimed in any one of claims 1 to 3, inwhich said steam-permeable paper sheet material is selected from thegroup consisting of a synthetic resin sheet with a liner composed ofwood pulp and hydrophobic thermal shrinking fibers, a fibrous paper madeof only thermal shrinking fibers, and a fibrous paper partly containingthermal shrinking fibers.
 6. A heat-adhesive paper sheet as claimed inany one of claims 1 to 3, in which said thermoplastic, thermalshrinking, pressure-sensitive adhesive is selected from the groupconsisting of EVA, EEA, EAA, ionomer resins, urethane resins andderivatives thereof.
 7. A heat-adhesive paper sheet as claimed in anyone of claims 1 to 3, in which said steam-permeable paper sheet materialhas said thermoplastic, thermal shrinking, pressure-sensitive adhesivelayer provided on one surface thereof and has a material selected fromthe group consisting of a woven fabric, knitted fabric, non-wovenfabric, heat resistant synthetic resin layer, thin cork skin, thin woodskin, metal foil, mineral net and leather, laminated on the oppositesurface thereof.
 8. A heat-adhesive paper sheet as claimed in any one ofclaims 1 to 3, in which said steam-permeable paper sheet materialcontains inorganic fibers.